<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body {
      width: 100%;
      height: 1123px;
      background: linear-gradient(173deg, #F5F8FF 20%, #E1E9FC 80%, rgba(225, 233, 252, 0) 86%);
      display: flex;
      justify-content: center;
      align-items: center;
    }
  </style>
</head>
<body>
  <h1>我是封面</h1>
</body>
</html>